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rebuilding transfer case

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
Hey guys, I have a bit of a whine in my driveline and I think it's coming from the transfer case, as there's a leak from the rear shaft (probably the seal or the driveshaft yolk) - anyway I think I went too long between topping it up and may have run it close to dry.

Is it easy enough to do the job, do I need access to specialist tools like bearing pullers etc? What usually gets replaced when rebuilding the transfer case, gather just bearings and seals? Would you bother replacing the gears too if they have little to no noticeable wear?

Also, I have two oil seals MR983368 'O/SEAL, M/T' in my box of bits from the previous owner - I can't match them up to any of the oil seals for the gearbox or transfer case in CAPS, does anyone know what these seals are for? Am thinking maybe driveshaft seals as there's a pair of them.

Thanks!
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581


It's actually pretty straightforward to get to here.

Begin by draining the t-case while it's still installed on the vehicle.

Draining the oil into a clean drain pan will give some insight into the internal condition, (as will how "fuzzy" the drain magnet is.)

Reinstall the plugs finger tite and remove the t-case.




Support the drained t-case as shown and give it a sharp rap with a plastic deadblow hammer.




Use a pry bar as shown to gently work the case apart.

Do NOT pound on the case to seperate them!

Easy does it, just work it untill it seperates cleanly. Using leverage as shown above will help considerably.




Remove the oil rail before cleaning the rear case section.
A standard solvent (like stoddards) will make quick work of the residual oil/grunge.
Brake clean can also be used. (pm Curtis for a recomondation on the best product, he snorts it like it's going out of style, so he's the board "authority" on which product has the fruitest "bouquet" /ubbthreads/images/graemlins/devil.gif

Do NOT use brake clean on the drip rail, it may deteriorate the plastic! A wipe with a clean rag should do it just fine.

errr, where was I? ...

Remove the nose case cover bolts,



... and then to remove the cover, gently tap on the splined side of the front shaft, (as indicated by the arrow ) and use the shaft to knock the cover out of the case.

Remove the front shaft and place it in a ziploc bag to keep it clean.




Seperate the intermidate case from the nose casing as shown, making sure to note there's a shim there!
Be sure to replace the o-ring on reassembly!



Most of the outer races in the case will slide out without speciality tools, as they fit fairly loosely in their bores.



A little heat applied to the case (not the race!) while using a roll punch/lady fingers ( like in the pic above^ )under the race will usually see them on the bench in short order.


Note the relief under the race.




A 90* pick in that relief will get about half of them without heat, so try that first before you break out heat/special tooling. ( easy is as easy does! ) be very carefull you don;t scratch the bores! any burrs can keep things from seating properly on reassembly!



Note that some races fit so loosely the race will rotate in service!
This does all kinds of bad things to the shim!





each and every shim must be measured at several points to get a good feel for whether they have been damaged to the point you need to replace them.





The inner races press on the shafts with a pretty tight interference fit, so you will need pullers for those. There are several choices, and I usually end up using a combination of every damn arm in the puller cabinet ... but, with a little patience there's nothing you can;t overcome if you have the full puller set.

be very carefull to identify each shim pack and be sure they go back from where they came! (used egg cartons work well for this, as do zip-loc bags. some of the shims are very thin and can be damaged easily. (replacements are available, but you'll have to wait for them to ship, extending your downtime)

[sorry, dinner time, gots to go! If you would like I can continue at a later date]

John
 

fuel

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Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
thank you very much John you are a God send!
 

Barnes

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Feb 9, 2003
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6,249
Location
Richland, WA
Are used good condition transfer cases hard to come by in New Zealand? Seems like a lot of work if you could just buy a replacement one for cheap.
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
yeah there is generally a supply of used transfer cases.. but they are just that - used. I don't know if they haven't been run dry at some point in their life etc. Mine is an iron head 23 spline unit which is specific to the Evolution VR-4, but the CD5A Lancer GSR (not Evolution) uses the same transfer case so there should be a few of them to choose from. The previous owner of my car went to great lengths to make the car top notch, even rebuilding the engine when it didn't necessarily require it. I'm hoping to follow on with his theme with a rebuilt transfer case with painted/polished housings and even new or re-coated bolts for a little bit of under-body bling. That said if it's going to be more than say $300 in parts to rebuild the transfer case I will probably flag the idea and find a good used one.
 

DR1665

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Oct 19, 2005
Messages
4,643
Location
Iowa City, IA
Wow. He shoots. He scores.

I might try this (though the fluid I got outta mine was almost black and very sparkley). :/
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
after speaking with the previous owner it turns out the t-case in mine is an EvoII item after the original one managed to strip splines on the input shaft. In CAPS they have differing part numbers but the ratio is the same and the spline count is the same, so I guess it's close enough.
 

toybreaker

iconoclast
Joined
Apr 30, 2006
Messages
3,581
Phil,


If the unit was fine before it was run lowish, a quick look thru the inspection plate will tell if it's worth spending any time on.




Youre looking for a good even pattern, with no material loss.

If there's any chips or chunks out of the gear teeth ...

... give it the navy "floatation" test (find the nearest body of water, toss it in, and if it floats, you can use it! )

Now, look at the teeth more closely.




The two gears meshing will wear a series of witness marks/polished smooth areas into the gearset teeth, and they tell the tale of how well the gearset was enjoying it's life, and how much life is left.

You're looking for a smooth contact pattern that does not run off the edge of the tooth. It should be mostly centered, but most of all it should be smooth, without any noticeable "denting" (areas worn away)


(click on pic to enlarge)

Notice the area in the circle that has a "smeared" appearance, (and also notice the wear pattern has some depth to it.)

This wear pattern forms when the bearing preload is lost and the shafts can "tip" a schoshe under load, concentrating the loading on a smaller area. (or you;re making a sh*t ton of power /ubbthreads/images/graemlins/devil.gif ). ( It can also form if your fluid isn't up to the task, but there will be other signs of that in other areas. )

At any rate, I don;t like running gearsets with this kind of pattern, as they almost invariably come back and bite me in the ass.









Check the splines on the coupler, (post a pic if you can)


If it passes both those quick checks, it's worth spending some more time on.


Starting with it clean on the outside will help considerably when you want to put it together clean on the inside!

cap the end and wrap it with tape.

Remove the breather and plug the hole with a #3x plastic cap. (or whatever you have that fits the hole in the case tightly)

Hose that nasty bitch down with engine degreaser (... don't kno if Curtis is a connoisseur of degreasers, maybe he can chime in /ubbthreads/images/graemlins/devil.gif ) and wash the thing thoroughly. Often a small plastic dishbrush will help working the cleaner into the shmeg, and it'll come cleaner faster and more better if you work the really grungy spots.

Thoroughly clean the coupler splines. A "bottle" brush from the dollar store will really make this job easier!

When you;re done washing it, pull the tape and cap off the back end and stand it up in a drain pan to let any water they may gotten in to drain out.

I usually hose the coupler splines with wd-40 at this point, and then blow the thing dry with compressed air. (wear safety gasses!)




Quoting Barnes:
Are used good condition transfer cases hard to come by in New Zealand? Seems like a lot of work if you could just buy a replacement one for cheap.



... Having an "issue" with a t-case can turn deadly serious in an instant ...

Do you want to trust your ass to a case you know nothing about?



"Good" condition used t-cases are already hard to find, and most that you will find will be high mileage pieces of sh*t




... with worn out splines in the coupler ...

In his home country, they never "officially" got the vr-4. All the vr-4's running sround there were imported after the fact, and that makes finding replacement parts hit and miss.


I've just about given up on finding cheap and/or even "good" cores, and now I'm just resigned to the fact that they will need some love before they are worthy of being installed on my car, ( or the car of anyone I care about. )

... and that's here in the states where there's a lot more cars, including the T/E/L chassis to choose from ...



At the very least, before I spend my hard earned sheckles on a pig in a poke, I'll pull the inspection plate and look at the gear contact pattern.

... And before I run it, I'll open it up and inspect the bearing races, and the tooth contact pattern more closely ...

Yeah, sounds like work, don;t it?

Guess I'm just used to relying on my sh*t to get me there and back, and I know what it takes to ensure it happens that way.

chance favors a prepared ride /ubbthreads/images/graemlins/smile.gif
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
wow John thank you for that wealth of information! When I have an afternoon free I will get the whale up on jack stands and pull the t-case out for inspection.
 

DR1665

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Joined
Oct 19, 2005
Messages
4,643
Location
Iowa City, IA
Sheckels on a pig in a poke. Nice!

Now I know I'm going to open that roached t-case in the garage. If it's slag, it's gone.
 

GSX_TC

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Joined
Apr 7, 2011
Messages
3,725
Location
Houston, Texas
I wish all posts were like john's
 
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